Scalable Production of Cardiomyocytes Derived from c-Myc Free Induced Pluripotent Stem Cells

Cardiomyocytes derived from induced pluripotent stem (iPS) cells hold great promise for basic and translational cardiovascular research. For the successful implementation of this unique technology, however, it is essential to establish efficient, reproducible, and safe strategies to produce cardiomyocytes in a scalable manner. The aim of the current study was to establish scalable bioprocess that allows direct embryoid bodies formation for the differentiation of murine iPS cells (generated without the oncogene c-Myc) into cardiomyocytes. The cardiomyocytes' structural, molecular, and functional properties were then compared to ones derived by the well-established static culture system. Similar gene expression patterns were observed in both differentiation systems with the sequential expression of mesoderm markers, cardiac transcription factors, and cardiomyocyte structural genes. Cells in the contracting embryoid bodies were stained positively for cardiac troponin-I, sarcomeric alpha-actinin, cardiac troponin-T, and connexin-43. Electrophysiological measurements using multielectrode array recordings demonstrated that the bioreactor-derived cardiomyocytes were functionally similar to static derived cardiomyocytes and responded appropriately to different drugs, including adrenergic and muscarinic agonists (isoproterenol and carbamylcholine, respectively) and the gap junction uncoupler heptanol. Our study describes, for the first time, a strategy for scalable differentiation of c-Myc-free iPS cells into cardiomyocytes with the appropriate molecular, structural, and functional properties. The result of this study should have important implications for several cardiovascular research areas and specifically for the emerging field of regenerative medicine.